1. Field of the Invention
The present invention relates to an optical connector which is formed by processing an end portion of an optical fiber and used for butting end faces of optical fibers against each other so as to optically connect them to each other.
2. Related Background Art
A conventional optical connector has been produced by the steps of causing an adhesive to flow into an optical fiber insertion hole formed in a connector ferrule body, inserting an optical fiber therein, so as to secure the optical fiber to the connector ferrule with the adhesive, and then grinding a connection end face of the optical connector. As a consequence, the connection end face of the optical connector and the tip face of the optical fiber are made flush with each other, so that connector ferrules can securely couple with each other. Japanese Patent Application Laid-Open No. SHO 61-156207 discloses an example of such techniques.
It has been difficult for such an optical connector to securely prevent the adhesive from attaching to the tip face of the connector ferrule. A precise end face grinding step is necessary for eliminating the attached adhesive, so that it takes time to assemble the optical connector, while expensive equipment is necessary for carrying out precise grinding, and so forth. Hence, this optical connector has not been suitable for assembly at the site of installation.
In order to overcome the above-mentioned problems, it is an object of the present invention to provide an optical connector which can shorten its assembling time and can be assembled easily at a lower cost.
In the optical connector in accordance with the present invention, for overcoming the above-mentioned problems, an end face of an optical fiber is disposed within a fiber positioning hole, a part of the optical fiber having a predetermined length from the end face side thereof is held axially slidable within the optical fiber positioning hole, the optical fiber is secured by an area thereof subsequent to the predetermined length part to a connector ferrule body, and a refractive index matching material is filled the optical fiber positioning hole at least from a front end face of the connector ferrule body to the end face of the optical fiber.
In this optical connector, an end face of the optical fiber is formed into a state buried in the optical fiber positioning hole and retracted from the front end face of the connector ferrule (corresponding to the connection end face of the optical connector). Also, the optical fiber positioning hole is filled with the refractive index matching material at least from the front end face of the connector ferrule to the end face of the optical fiber. When such optical connectors are caused to face each other and optical fibers are optically connected to each other, the refractive index matching material is interposed between the end faces of the optical fibers, whereby optical connections can be realized with a low loss regardless of the form of the tip faces of optical fibers. As a consequence, the conventional precise grinding step becomes substantially unnecessary, whereby the assembling time of the optical connector can be shortened. Also, since the end portion of the optical fiber is disposed axially slidable within the optical fiber positioning hole, the optical fiber is allowed to thermally expand and contract, whereby loss can be kept from increasing due to extra stresses applied to the optical fiber.
Behind the optical fiber positioning hole, the connector ferrule body may be provided with an optical fiber alignment groove, so that the optical fiber is contained in the optical fiber alignment groove and secured thereto by bonding. Alternatively, the optical connector may further comprise an optical fiber pressing and securing member for securing the optical fiber contained in the optical fiber alignment groove by pressing the optical fiber against a wall face of the optical fiber alignment groove.
According to these configurations, the optical fiber alignment groove is used as a guide groove, so that it becomes easier to insert the optical fiber into the optical fiber positioning hole, while the adhesive can effectively be prevented from flowing into the optical fiber positioning hole in the case where the optical fiber is secured with the adhesive in particular, whereby they are advantageous in that manufacture becomes easier.
Preferably, the end face of the optical fiber is treated by an edge elimination. When the end face of the optical fiber is rounded by an edge elimination, the insertion of the optical fiber becomes easier, and the tip face of the optical fiber can effectively be restrained from chipping off within the optical fiber positioning hole, whereby operations can be made faster. For the edge elimination, electrical discharge machining or grinding can be employed.
The connector ferrule body may have a plurality of optical fiber positioning holes each containing an optical fiber. As a consequence, optical connections with a low loss can be realized when making an optical connector in which a plurality of optical fibers are end-coupled even if the end faces of the optical fibers do not accurately align with each other. For example, even when an end portion of an optical fiber ribbon is processed to yield an optical connector, the tip faces of individual optical fibers are allowed to be somewhat uneven without being processed to accurately align with each other when the end portion of the optical fiber ribbon is processed before the optical fibers of the optical fiber ribbon are inserted into the connector ferrule. Hence, the cutting can be carried out rapidly, which contributes to shortening the assembling time of the optical connector.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings. They are given by way of illustration only, and thus should not be considered limitative of the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it is clear that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, and various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.